Morphine-based Pain Relief Could Influence Spread of Cancer Cells
New research, led by Prof. Donal Buggy (UCD Associate Professor of Anaesthesia and Consultant in Anaesthesia, Mater Misericordiae University Hospital) which will be published in the British Journal of Anaesthesia*(1), indicates that the type of anaesthetic used during surgery could affect the metastatic potential of cancer cells.
The research involved taking the blood before and after surgery from breast cancer patients who had been given different types of anaesthetic and pain relief. Some had used standard inhaled general anaesthetics with morphine-based pain relief*(2), and others had been anaesthetised using regional techniques with a single intravenous general anaesthetic (propofol) to minimize morphine dosing*(3). In laboratory conditions, breast cancer cells were then exposed to these blood samples.
Researchers found that the blood from patients who had been given standard inhaled general anaesthetics with morphine pain relief reduced apoptosis. In contrast, cancer cells exposed to blood from patients who had been given regional anaesthesia and propofol showed a higher rate of apoptosis.
In separate research also carried out at the School and also to be published in this Special Issue of the British Journal of Anaesthesia on Cancer and Anaesthesia*(4), laboratory tests indicate that anaesthetic technique can affect the activity of the body’s immune system and its Natural Killer (NK) cells. Blood from breast cancer patients was exposed to NK cells and breast cancer cells. The blood from patients who had been given regional anaesthesia and propofol resulted in more Natural Killer cell anti-cancer activity than the blood from patients who received standard inhaled general anaesthetics with morphine pain relief.
Professor Buggy points out that these laboratory results are not conclusive and there is not currently enough evidence to indicate cancer patients should choose one anaesthetic technique over another. However, he is calling for funding for ongoing research to ascertain if changing anaesthetic techniques could ultimately benefit cancer patients.
While this research is laboratory based, there is a groundswell of evidence that indicates anaesthesia and pain relief technique during cancer surgery may influence the risk of cancer recurrence. What is needed now is definitive evidence. Traditionally this type of research has not been prioritised by major awarding bodies, and consequently trials have been restricted in scope. The only way cancer surgery patients can know if anaesthetic technique could affect the spread of the disease is a commitment to large scale clinical trials.
*(1) Differential effects of serum from patients administered distinct anaesthetic techniques on apoptosis in breast cancer cells in vitro: a pilot study, BJA Article AET 581
*(2) Patients were given standard sevoflurane general anaesthesia with opioid analgesia (SGA)
*(3) Patients were given regional numbing and propofol general anaesthesia with paravertebral analgesia (PPA)
*(4)Effect of anaesthetic technique on the natural killer cell anti-tumour activity of serum from women undergoing breast cancer surgery: a pilot study BJA Article AEU 200